SE544760C2 - A battery circuit with parallel battery systems and battery testing means, and a method, for a vehicle - Google Patents

A battery circuit with parallel battery systems and battery testing means, and a method, for a vehicle

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Publication number
SE544760C2
SE544760C2 SE2150306A SE2150306A SE544760C2 SE 544760 C2 SE544760 C2 SE 544760C2 SE 2150306 A SE2150306 A SE 2150306A SE 2150306 A SE2150306 A SE 2150306A SE 544760 C2 SE544760 C2 SE 544760C2
Authority
SE
Sweden
Prior art keywords
battery
primary
voltage
circuit
vehicle
Prior art date
Application number
SE2150306A
Other languages
Swedish (sv)
Other versions
SE2150306A1 (en
Inventor
Gunnar Ledfelt
Lukas Rydén
Original Assignee
Scania Cv Ab
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Scania Cv Ab filed Critical Scania Cv Ab
Priority to SE2150306A priority Critical patent/SE544760C2/en
Priority to DE102022104303.7A priority patent/DE102022104303A1/en
Publication of SE2150306A1 publication Critical patent/SE2150306A1/en
Publication of SE544760C2 publication Critical patent/SE544760C2/en

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0023—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train
    • B60L3/0046—Detecting, eliminating, remedying or compensating for drive train abnormalities, e.g. failures within the drive train relating to electric energy storage systems, e.g. batteries or capacitors
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/14—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
    • H02J7/1423—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle with multiple batteries
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/0092—Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption with use of redundant elements for safety purposes
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L50/00—Electric propulsion with power supplied within the vehicle
    • B60L50/50—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells
    • B60L50/60—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries
    • B60L50/61—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles
    • B60L50/62—Electric propulsion with power supplied within the vehicle using propulsion power supplied by batteries or fuel cells using power supplied by batteries by batteries charged by engine-driven generators, e.g. series hybrid electric vehicles charged by low-power generators primarily intended to support the batteries, e.g. range extenders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/12—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries responding to state of charge [SoC]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/21—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules having the same nominal voltage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L58/00—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles
    • B60L58/10—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries
    • B60L58/18—Methods or circuit arrangements for monitoring or controlling batteries or fuel cells, specially adapted for electric vehicles for monitoring or controlling batteries of two or more battery modules
    • B60L58/22—Balancing the charge of battery modules
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/392—Determining battery ageing or deterioration, e.g. state of health
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/40—Testing power supplies
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2200/00—Type of vehicles
    • B60L2200/36—Vehicles designed to transport cargo, e.g. trucks
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/547—Voltage
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00—Control parameters of input or output; Target parameters
    • B60L2240/40—Drive Train control parameters
    • B60L2240/54—Drive Train control parameters related to batteries
    • B60L2240/549—Current
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2260/00—Operating Modes
    • B60L2260/20—Drive modes; Transition between modes
    • B60L2260/32—Auto pilot mode
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/005—Testing of electric installations on transport means
    • G01R31/006—Testing of electric installations on transport means on road vehicles, e.g. automobiles or trucks
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/382—Arrangements for monitoring battery or accumulator variables, e.g. SoC
    • G01R31/3835—Arrangements for monitoring battery or accumulator variables, e.g. SoC involving only voltage measurements

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Sustainable Energy (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Secondary Cells (AREA)

Abstract

A method and a battery circuit design by means of which the functionality of a primary battery (102) of a primary battery circuit (101) and the functionality of a secondary battery (105) of a secondary battery circuit (104) connected to the primary battery circuit (101) are determined by means of measurement voltages at an input (108) and an output (109) of a control circuit (100) connecting the primary battery circuit (101) with the secondary battery circuit (104), without use of additional battery test switches.

Description

TECHNICAL FIELD The present invention relates to a method of generating a battery status signal of a battery circuit for a vehicle. The invention also relates to a battery circuit for a vehicle and more particularly to a battery circuit with a primary battery and a secondary battery with the same nominal voltage.
BACKGROUND ln modern vehicles there is often at least two parallel battery systems. Often these systems comprises a primary battery and a secondary battery connected in parallel for providing redundancy in power supply for critical systems. This is especially important for autonomous vehicles that have safety systems for monitoring and control of the vehicle that must be operational for safety reasons. lt is important that both the primary battery and the secondary battery is operational and functional. ln a driver-operated vehicle having a pneumatic breaking system, the driver is able to manually introduce into the pneumatic breaking system the power needed in order to activate breaking. A battery failure during travel is thus not so critical with regard to breaking capacity for a driver-operated vehicle. ln an autonomous vehicle, however, there is no such further power available. ln an autonomous vehicle, a redundant electric system that enables breaking also upon loss of battery power is thus desirable. Such a system may comprise a primary battery circuit in which redundancy is guaranteed by a generator, and a secondary battery circuit in which the redundancy is guaranteed by the primary battery of the primary battery circuit. ln prior art several solutions for determining the function of the batteries are known. These solutions often employ a set of controlled switches that are used to isolate the battery under test. Such switches causes complexity in the battery circuit that connects the primary and secondary battery. The present invention is based on a design in which such controlled additional switches are not used, but where, instead, a connection circuit between a primary battery circuit and a secondary battery circuit is taken advantage of for the purpose of determining the function of a primary battery in a primary battery circuit and a secondary battery in a secondary circuit respectiveiy.
SUMMARY lt is thus an object of the present invention to suggest a method and a battery circuit design by means of which the functionality of a primary battery of a primary battery circuit and the functionality of a secondary battery of a secondary battery circuit connected to the primary battery circuit can be determined without use of additional battery test switches.
The object of the invention is achieved by means of a method of generating a battery status signal of a battery circuit for a vehicle, wherein the battery circuit comprises: a primary battery circuit comprising: a primary battery; a generator, a controllable primary load connected to the primary battery; a secondary battery circuit comprising: a secondary battery; a controllable secondary load connected to the secondary battery; a connection circuit an input connected to a positive pole of the primary battery; an output connected to a positive pole of the secondary battery; a first branch which connects the input to the output, wherein the first branch comprises a diode arranged such that electric current may flow from the input to the output. The method further comprises: a) disabling the generator; b) setting the primary load at a first level; c) executing a measurement of a first voltage Vi1 at said input;d) comparing the measured first voltage Vi1 to a first threshold value, and generating a first battery status signal for the primary battery on basis of said comparison; e) enabling and setting the primary load at a second level, which is higher than the first level; f) executing a measurement of a second voltage Vi2 at said input; g) comparing the measured second voltage Vi2 to the measured first voltage Vi1, and generating a second battery status signal for the primary battery, based on said comparison; h) enabling the secondary load and enabling the primary load i) executing a measurement of a third voltage Vi3 at the input and a measurement of a fourth voltage Vo4 the output; j) comparing the third voltage and the fourth voltage Vo4, and generating a first battery status signal for the secondary battery based on basis of said comparison. ln this context, the term enabling may be referred to as connecting and making functionally active. The first level of the primary load may comprise also zero load.
According to one embodiment, the battery status signal indicates a primary battery error if the first voltage Vi1 is not above said first threshold value Vth According to one embodiment, the first threshold value is 20%, preferably 10%, of the nominal voltage VpN of the primary battery.
As defined in this application, the nominal voltage of the battery is determined in accordance with IEC Standard 60050-482: According to one embodiment, the battery status signal indicates a primary battery error if the difference between the first voltage Vi1 and the second voltage Vi2 is above a second threshold value, which is a predetermined percentage of a nominal voltage VpN of the primary battery.According to one embodiment, the second threshold value is 20 % of the nominal voltage VpN of the primary battery, preferably 15% of the nominal voltage VpN of the primary battery, even more preferably 10% of the nominal voltage VpN of the primary battery.
According to one embodiment, the method is characterized in that, in step j), the first battery status signal for the secondary battery indicates a secondary battery error if the difference between the third voltage Vi3 and the fourth voltage Vi4 is above a third threshold value, which third threshold value is the voltage at which the diode admits flow of current from said input to said output.
According to one embodiment, the method is characterized in that if, in step S10, Vi3- Vo4>Vth3, the secondary load is reduced and steps S9 and S10 are repeated until a predetermined level of the secondary load is arrived at, or until Vi3-Vo4 According to one embodiment, the method is characterized in that if, in step S7, Vil- Vi2 According to one embodiment, a relative level of the secondary load enabled in step h) is lower than a relative level of the primary load enabled in step h). ln this context relative is referred to as compared to a nominal capacity of the respective primary and secondary battery. A “relative level” as referred to in this context, is the effect that the respective load has on the measured voltage of its associated battery.According to one embodiment, the primary battery and the secondary battery have the same nominal voltage.
The object of the invention is also achieved by means of a battery circuit for generating a battery status signal for a vehicle, comprising: a primary battery circuit comprising: a primary battery; a controllable primary load connected to the primary battery; a generator connected to the primary battery; a secondary battery circuit comprising: a secondary battery; a controllable secondary load connected to the secondary battery.
The battery circuit further comprises a connection circuit comprising: an input connected to a positive pole of the primary battery; an output connected to a positive pole of the secondary battery; a first branch which connects the input to the output, wherein the first branch comprises a diode arranged such that electric current may flow from the input to the output; a control circuit, comprising: a first voltage detector configured to measure the voltage of the input; a second voltage detector configured to measure the voltage of the output; a primary output configured to control the connection of the controllable primary load to said primary battery; a secondary output configured to control the connection of the controllable secondary load to said secondary battery; an output for a battery status signal; wherein the control circuit is configured to execute the method according the present as defined hereinabove.The object of the invention is also achieved by means of a vehicle battery system, comprising: a battery circuit according to the invention, as defined hereinabove, further comprising an enable signal input, which upon activation causes the control circuit to generate the battery status signal; a generator connected to the primary battery for charging thereof; a vehicle controller configured to receive said battery status signal and to receive a vehicle standstill signal, wherein the vehicle controller is configured to control the generator, the vehicle controller further comprises an enable output connected to said enable signal input of the battery circuit, wherein the vehicle controller is further configured to turn off said generator and enable said enable signal input, upon receiving said vehicle standstill signal, and wherein the vehicle controller is also configured to generate a safety stop signal, upon detection of a battery error in the battery status signal.
The invention also relates to a vehicle comprising a vehicle battery system according to the invention, as defined hereinabove or hereinafter.
According to one embodiment, the vehicle is an autonomous vehicle and upon detecting a battery error in the battery status signal the autonomous vehicle initiates a safety stop.
The invention also relates to a computer-readable storage medium storing computer program instructions which, when executed by a processor, cause the processor to perform a method as set out hereinabove or hereinafter.
The inventions also relates to a signal carrying computer program instructions which, when executed by a processor, cause the processor to perform a method as set out hereinabove or hereinafter.
Further features of the invention will be disclosed in the following detailed description of em bodiments.
BRIEF DESCRIPTION OF THE DRAWING Embodiments of the invention will be described with reference to the annexed drawing, on which Fig. 1 is a battery circuit according to the present invention, Fig. 2 is a vehicle controller, Fig. 3 is a vehicle carrying the battery circuit, Fig. 4 is a flow chart showing a first embodiment of a method according to the present invention, and Fig. 5 is a flow chart showing a second embodiment of a method according to the present invention.
DETAILED DESCRIPTION Fig. 1 shows a battery circuit 1 according to the present invention. The battery circuit 1 is arranged in a vehicle 300 (fig. 2) and thereby forms part of a vehicle electric system. The battery circuit 1 comprises a primary battery circuit 101 comprising a primary battery 102, a generator 116 and a controllable primary load 103 connected to the primary battery 102. The battery circuit 1 further comprises a secondary battery circuit 104 comprising a secondary battery 105, and a controllable secondary load 106 connected to the secondary battery 105, the battery circuit 1 also comprises a connection circuit having an input 107 connected to a positive pole of the primary battery 102, an output 108 connected to a positive pole of the secondary battery 105 and a first branch 109 which connects the input 107 to the output 108, wherein the first branch 109 comprises a diode D1 arranged such that electric current may flow from the input 107 to the output ln the embodiment shown, the primary battery 102 and the secondary battery 105 have the same nominal voltage. ln the embodiment shown, the primary load 103 comprise one or more of a heater, a fan or a pump device, and the secondary load 106 comprises one or more of a heater, a fanor a pump device. Preferably, each the effect of each individual load may be individualiy controlled.
The connection circuit 100 further comprises a control circuit 110, which in its turn comprises a first voltage detector 111 configured to measure the voltage of the input 107, a second voltage detector 112 configured to measure the voltage of the output 108, a primary output 114 configured to control the connection of the controllable primary load 103 to said primary battery 102, a secondary output 115 configured to control the connection of the controllable secondary load 106 to said secondary battery 105, and an output 1 13 for transmission ofa battery status signal. The control circuit 110 is configured to execute a method according the invention as defined hereinabove and/or hereinafter.
The battery circuit 1 further comprises an enable signal input 118, which upon activation causes the control circuit 110 to generate the battery status signal. The battery circuit 1 also comprises a vehicle controller 121 configured to receive said battery status signal and to receive a vehicle standstill signal, wherein the vehicle controller 121 is configured to control the generator 116, and the vehicle controller 121 further comprises an enable output 113 connected to said enable signal input 118 of the battery circuit 1. The vehicle controller 121 is further configured to turn off the generator 116 and enable said enable signal input 118, upon receiving said vehicle standstill signal. Furthermore, the vehicle controller 121 is configured to generate a safety stop signal, upon detection of a battery error in the battery status signal.
Fig. 3 shows an exemplary implementation of the control circuit 110 using programmable signal processing hardware 400. The signal processing apparatus 400 shown in Fig. 3 comprises an input/output section 410 for receiving and transmitting signals to the control circuit 110 as indicated in Fig. 1. The signal processing apparatus 400 further comprises a processor 420, a working memory 430 and an instruction store 440 storing computer-readable instructions which, when executed by the processor 420, cause the processor 420 to perform processing operations herein described. The instruction store 440 may comprise a ROM which is preloaded with computer readable instructions. Alternatively, instruction store 440 may comprise a RAM or similar type ofmemory, and the computer readable instructions can be input thereto from a computer program product, such as a computer readable storage medium 450 such as a CD- ROM, etc. or a computer readable signal 460 carrying the computer readable instructions.
The first branch 109 of Fig. 1 further comprises a fuse F1 arranged to protect the diode D1 against over current. The diode D1 is a diode with low forward voltage drop and of high current type, such as for example a Schottky power diode. The fuse F1 of the first branch 109 also protects the primary battery circuit 101 in case of a short-circuit in the secondary battery circuit According to one embodiment, the battery circuit 1 is configured to execute a method presented in fig. 4. The vehicle should be standing still when the method is applied. The method comprises the following steps: a) disabling S1 the generator 116. ln order to avoid functional loss lf the primary battery 102 is weak, the voltage of the generator may be reduced in a plurality of steps down to a predetermined voltage, as compared to the nominal voltage of the primary battery ; b) setting S2 the primary load 103 at a first level. ln one embodiment this level is zero; c) executing S3 a measurement of a first voltage Vi1 at said input 107; d) comparing S4 the measured first voltage Vi1 to a first threshold value Vth1, and generating a first battery status signal for the primary battery 102 on basis of said comparison. ln one embodiment, the first threshold value Vth1 is 10% of the nominal voltage of the primary battery. lf the first voltage is lower than that, the battery status signal will indicate primary battery failure, and the further testing is stopped, indicated with S4”. lf that is not the case, the testing continues with the following steps; e) enabling and setting S5 the primary load 103 at a second level, which is higher than the first level. According to one embodiment, the second level is at least 50%, of the maximum level of the primary load 103, and according to yet another embodiment the second level is at least 90% of the maximum level of the primary load 103; f) executing S6 a measurement of a second voltage Vi2 at said input 107; g) comparing S7 the measured second voltage Vi2 to the measured first voltage Vi1, and generating a second battery status signal for the primary battery 102, based on said comparison. lf Vi1-Vi2 is above a second threshold value Vth2, a battery status signal indicating primary battery failure is generated, and the further testing is stopped, indicated with S7”. According to one embodiment, the second threshold value Vth2 is 15% of the nominal voltage of the primary battery 102. lf the difference between Vi1 and Vi2 does not indicate primary battery failure, the testing proceeds with the following steps; h) enabling S8 the secondary load 106 and enabling the primary load 103. According to one embodiment, the primary load 103 is set at said second level. According to one embodiment, the secondary load 106 is at least 10% of the maximum level of the secondary load and not more than 60% of the maximum level of the secondary load 106; i) executing S9 a measurement of a third voltage Vi3 at the input 107 and a measurement of a fourth voltage Vo4 the output; j) comparing S10 the third voltage Vi3 and the fourth voltage Vo4, and generating a first battery status signal for the secondary battery 105 based on basis of said comparison. lf Vi3-Vi4 is above a third threshold value Vth3, the battery status signal indicates that the secondary battery 105 is weak, i.e. secondary battery failure, and further testing is inhibited, as indicated with S10”. According to one embodiment, Vth3 is the voltage at which a current will pass through the diode D1 from the primary circuit to the secondary circuit. According to one embodiment, Vth3 is 0.7V. lf, on the other hand, Vi3-Vi4 is below Vth3, this is an indication that also the secondary battery is functioning. ln such case, as a response to such a signal, the primary load 103 and the secondary load 106 are reset to zero and the generator 116 is re-enabled, step S11. The testing procedure is ended.
Fig. 5 shows a second embodiment, of the method. lf the primary load applied in step S5 of the embodiment disclosed with reference to fig. 4 is to low, there is a risk that that the diode D1 will open for flow of current through it, which will result in a wrong assessment of the condition of the primary battery 102. The method shown in fig.differs from the one shown in fig. 4 in that, as a response to step S7 indicating primarybattery functionality (Vi1-Vi2Vth4 and Vi1-Vi2 lf the level of the secondary load applied in step S8 in the embodiment disclosed with reference to fig. 4 is too high, there is a risk that that the diode D1 will conduct a flow of current through it, which will result in a wrong assessment of the condition of the secondary battery 105. The method shown in fig. 5 differs from the method shown in fig. 4 in that, if, in step S10, Vi3-Vo4>Vth3, the testing procedure is continued by applying a loop, comprising a step S10A in which the secondary load 106 is reduced a predetermined amount and step S9 and S10 are repeated. The loop comprising steps S10A, S9 and S10 is repeated until the secondary load reaches a predetermined level. lf the comparison between Vi3 and Vo4 then still results in Vi3-Vo4 being above the third threshold value Vth3, then a battery status signal indicating secondary battery failure is generated. The loop-comprising step S10A is thus applied since there is a risk that the initial level of the secondary load, applied at the first measurement of Vi3 and Vo4, was too high such that the diode D1 started to conduct a current.

Claims (12)

1. A method of generating a battery status signal of a battery circuit (1 ) for a vehicle (300), wherein the battery circuit (1) comprises: a primary battery circuit (101) comprising: a primary battery (102); a generator (116), a controllable primary load (103) connected to the primary battery (102); a secondary battery circuit (104) comprising: a secondary battery (105); a controllable secondary load (106) connected to the secondary battery (105); a connection circuitgíglå an input (107) connected to a positive pole of the primary battery (102); an output (108) connected to a positive pole of the secondary battery (105); a first branch (109) which connects the input (107) to the output (108), wherein the first branch (109) comprises a diode (D1) arranged such that electric current may flow from the input (107) to the output (108); characterized in that the method comprises: a) disabling (S1) the generator; b) setting (S2) the primary load at a first level; c) executing (S3) a measurement of a first voltage Vi1 at said input (107); d) comparing (S4) the measured first voltage Vi1 to a first threshold valuej; and generating a first battery status signal for the primary battery on basis of said comparison; e) enabling and setting (S5) the primary load at a second level, which is higher than the first level; f) executing (S6) a measurement of a second voltage Vi2 at said input (107);g) comparing (S7) the measured second voltage Vi2 to the measured first voltage Vi1, and generating a second battery status signal for the primary battery, based on said comparison; h) enabling (S8) the secondary load and enabling the primary load i) executing (S9) a measurement of a third voltage Vi3 at the input and a measurement of a fourth voltage V04 at the output; j) comparing (S10) the third voltage Vi3 and the fourth voltage Vo4, and generating a first battery status signal for the secondary battery on basis of said comparison.
2. The method according to claim 1, characterized in that the battery status signal indicates a primary battery error if the first voltage Vi1 is not above said first threshold value Vth
3. The method according to claim 1, characterized in that the first threshold value is 20%, preferably 10%, of the nominal voltage VpN of the primary battery (102).
4. The method according to any one of claims 1-3, characterized in that the battery status signal indicates a primary battery error if the difference between the first voltage Vi1 and the second voltage Vi2 is above a second threshold value Vth2, which is a predetermined percentage of a nominal voltage VpN of the primary battery.
5. The method according to claim 4, characterized in that the second threshold value is 20 % of the nominal voltage VpN of the primary battery, preferably 15% of the nominal voltage VpN of the primary battery, even more preferably 10% of the nominal voltage VpN of the primary battery.
6. The method according to any one of the preceding claims, characterized in that, in step j), the first battery status signal for the secondary battery indicates a secondary battery error if the difference between the third voltage Vi3 and the fourth voltage Vo4 is above a third threshold value Vth3, which third threshold value Vth3 is thevoltage at which the diode (D1) admits flow of current from said input (108) to said output (109) .
7. The method according to claim 6, characterized in that, if, in step S10, Vi3- Vo4>Vth3, the secondary load (106) is reduced (S10A) and steps S9 and S10 are repeated until a predetermined level of the secondary load (106) is arrived at, or until Vi3-Vo4
8. The method according to claims 1 and 4, characterized in that, if, in step S7, Vi1- Vi2
9. The method according to any one of claims 1-8, characterized in that a relative level of the secondary load enabled in step h) is lower than a relative level of the primary load enabled in step h).
10. The method according to any one of claims 1-9, characterized in that the primary battery and the secondary battery have the same nominal voltage.
11. A battery circuit (1) for generating a battery status signal for a vehicle, comprísing: a primary battery circuit (101) comprising: a primary battery (102); a controllable primary load (103) connected to the primary battery (102); a generator (116) connected to the primary battery (102); a secondary battery circuit (104) comprising: a secondary battery (105); a controllable secondary load (106) connected to the secondary battery (105); characterized in: that the battery circuit (1) further comprises a connection circuit (100) comprising: an input (107) connected to a positive pole of the primary battery (102); an output (108) connected to a positive pole of the secondary battery (105); a first branch (109) which connects the input (107) to the output (108), wherein the first branch (109) comprises a diode (D1) arranged such that electric current may flow from the input (107) to the output (108); a control circuit (110), comprising: a first voltage detector (111) configured to measure the voltage of the input (107); a second voltage detector (112) configured to measure the voltage of the output (108); a primary output (114) configured to control the connection of the controllable primary load (103) to said primary battery (102); a secondary output (115) configured to control the connection of the controllable secondary load (106) to said secondary battery (105); an output (113) for a battery status signal; wherein the control circuit (110) is configured to execute the method according to any one of claims1 to
12. A vehicle battery system comprising: a battery circuit according to claim 11, further comprising an enable signal input (118), which upon activation causes the control circuit (110) to generate the battery status signal; a vehicle controller (121) configured to receive said battery status signal and to receive a vehicle standstill signal, wherein the vehicle controller (121) is configured to control the generator (116), and the vehicle controller (121) furthercomprises an enable output (113) connected to said enable signal input (118) of the battery circuit (1), wherein the vehicle controller (121) is further configured to turn off said generator (1 16) and enable said enable signal input (118), upon receiving said vehicle standstill signal, and wherein the vehicle controller (121) is also configured to generate a safety stop signal, upon detection of a battery error in the battery status signal. A computer-readable storage medium (450) storing computer program instructions which, when executed by a processor (420), cause the processor (420) to perform a method as set out in at least one of claims 1 to A signal (460) carrying computer program instructions which, when executed by a processor (420), cause the processor (420) to perform a method as set out in at least one of claims 1 to A vehicle (300) comprising a vehicle battery system according to claim 12. The vehicle (300) according to claim 15, characterized in that the vehicle is an autonomous vehicle and upon detecting a battery error in the battery status signal the autonomous vehicle initiates a safety stop.
SE2150306A 2021-03-18 2021-03-18 A battery circuit with parallel battery systems and battery testing means, and a method, for a vehicle SE544760C2 (en)

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EP0753925A2 (en) * 1995-07-13 1997-01-15 Société Anonyme dite: REGIE NATIONALE DES USINES RENAULT Electrical supply device for a motor vehicle and methods for control of such a device
EP1467464A1 (en) * 2001-12-27 2004-10-13 Lear Automotive (EEDS) Spain, S.L. Circuit and method of controlling vehicle battery charges
US20150084345A1 (en) * 2011-05-14 2015-03-26 Volkswagen Ag Motor vehicle electrical system and method for operating a motor vehicle electrical system
US20180291857A1 (en) * 2017-04-10 2018-10-11 Subaru Corporation Vehicle power supply apparatus

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0753925A2 (en) * 1995-07-13 1997-01-15 Société Anonyme dite: REGIE NATIONALE DES USINES RENAULT Electrical supply device for a motor vehicle and methods for control of such a device
EP1467464A1 (en) * 2001-12-27 2004-10-13 Lear Automotive (EEDS) Spain, S.L. Circuit and method of controlling vehicle battery charges
US20150084345A1 (en) * 2011-05-14 2015-03-26 Volkswagen Ag Motor vehicle electrical system and method for operating a motor vehicle electrical system
US20180291857A1 (en) * 2017-04-10 2018-10-11 Subaru Corporation Vehicle power supply apparatus

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